67 Chevy and gmc dash harness' the same?

[chewychevy67]

I have a 67 gmc and am looking at getting a new wiring harness. All I can find for wiring is for chevy trucks. I know the front headlight harness is different because gmc has 4 eyes but is the under dash harness both with gauges different because of the headlights?

['68OrangeSunshine]

Originally Posted by chewychevy67

I have a 67 gmc and am looking at getting a new wiring harness. All I can find for wiring is for chevy trucks. I know the front headlight harness is different because gmc has 4 eyes but is the under dash harness both with gauges different because of the headlights?

The dash harness would be the same for a Chevy and a GMC. Only difference electrically is extra headlamp leads on the front engine/lighting harness for 4 x 5.25'' headlights instead of 2 x 7''.
Jimmys and Blazers will likely have Courtesy Lights under dash, since cab dome lights are not possible with a removeable top.

[chewychevy67]

So the front leads for high beams and low beams would just double from the bulkhead connection on the engine side because of the quad headlights correct?

['68OrangeSunshine]

Originally Posted by chewychevy67

So the front leads for high beams and low beams would just double from the bulkhead connection on the engine side because of the quad headlights correct?

Actually the inboard headlamps are High beams only. There is a parallel extension pigtail from each outboard headlamp connector that hooks up to the highbeams. Three leads for Hi Lo Grnd on the outboard head light. Two leads Hi Grnd on the inboard.

[chewychevy67]

Ok that makes sense. So the engine/ starter harness would most likely be the same with gauges for both as well just the headlight engine side would be different.

['68OrangeSunshine]

Yup.

[midniteblues]

Be carefull here as a 67 "chevy's" do not illuminate the park/driving/turn signal lights at full pull of the switch.

The spade connector in the pig tails for a 67 turn sig/driving lite are slightly differnt from a 68 and on.

Now im speaking in the "67 chevys" but im not 100% sure the gmc's are the same way but i bet they are.

The 67's have one spade set at a slight angle and the other is straight.
68' and on will have one spade vertical and the other horizonal.

One can always cut the oe rubber connectors off and re do them to fit with the correct ends.

Just some food for thought here.

['68OrangeSunshine]

Originally Posted by midniteblues

Be carefull here as a 67 "chevy's" do not illuminate the park/driving/turn signal lights at full pull of the switch.

The spade connector in the pig tails for a 67 turn sig/driving lite are slightly differnt from a 68 and on.

Now im speaking in the "67 chevys" but im not 100% sure the gmc's are the same way but i bet they are.

The 67's have one spade set at a slight angle and the other is straight.
68' and on will have one spade vertical and the other horizonal.

One can always cut the oe rubber connectors off and re do them to fit with the correct ends.

Just some food for thought here.

This is all true. If you're ordering a new harness from M&H or AAW, be sure to specify the year, as '67 has some unique features. I don't have a '67 GMC, but I would guess the only difference would be the 4 vs 2 lights.
If you're cannibalizing a harness off a later truck, you'll have to modify accordingly.
As Midnite says, the Park lights go out when the main headlights go on. Also no ACC setting on the starter switch. Both "Normal" for MY 1967. No side marker lights either. True for Chevy and GMC.
I hit a deer in my '67 K/10 Suburban, twenty-something years ago, and I got a '68 grille from a junkyard. It fit perfect, mechanically, but when I tried to connect the '68 Running lights to the '67 Park light connectors, I ran into the slanted terminal thing. So I reused my '67 Park light buckets and used the best looking amber lenses.

[chewychevy67]

All you have to do is move the brown wire on the headlight switch pigtail on 68 up to make them come on like 67's. My under dash harness is uncut and very nice. I was thinking about reusing it. But someone has removed the white writing on the fuse block and the terminals where the fuse clips in look rusty. I cleaned them best I can. Not sure if this will cause problems